Rammed earth embraced by Woods Bagot designers as a sustainable alternative to concrete

Rammed earth construction is having a design moment in Australia as part of a general move to more sustainable design, building and living practices.

Could it be the next big thing? Some think so and there’s no question it is gaining traction as a key design element in both commercial and residential projects, literally connecting them to the land on which they are built.

It’s been that way for thousands of years. Famous rammed earth structures include the Alhambra in Spain, large swathes of the Great Wall of China and Morocco’s Casbah Caid Ali – all of which demonstrate its practicality, versatility and durability.

Architecture studio Woods Bagot has embraced rammed earth, which typically exudes a unique, earthy character absent in contemporary manufactured counterparts, and is involved with two projects incorporating the material in Port Hedland and Sydney.

W-B Principal Jason Fraser says rammed earth possesses remarkable qualities that enable it to adapt to local weather conditions, making it an intelligent construction material choice.

“In the past, rammed earth was often considered unconventional, overshadowed by more mainstream choices,” says Fraser. 

“However, as we embrace a greater awareness of environmental impact, this material has the potential to challenge the dominance of concrete.”

Leading industry researcher Dr Jianfeng Xue, a Senior Lecturer in Geotechnical Engineering at UNSW Canberra, agrees that rammed earth is becoming more popular, especially for its economic and environmental benefits. 

“A really positive outcome of using rammed earth in buildings is that it reduces environmental impacts and greenhouse gas emissions,” says Dr Xue. 

Dr Xue is researching rammed earth technology for developer Molonglo to use in the residential element of its 14-hectare Dairy Road mixed-use development in Canberra. 

“The adoption of onsite soil in rammed earth structures significantly reduces the disposal of waste soils produced from site excavation and the use of imported materials,” he says.

“The outcomes of this project will provide a greater understanding of stabilised rammed earth and hopefully lead to a reduction in the amount of cement being used as a stabiliser, along with a reduction in construction costs,” he says.

Rammed earth walls at Port Hedland International Airport.

On the far northern coast of Western Australia, Woods Bagot has designed the extension of Port Hedland International Airport, where several rammed earth “blade” walls guide the passenger journey through the terminal. 

Project Leader Linda Randall says utilising rammed earth made sense on every level, including cost savings and sustainability benefits. 

“The airport is literally set in red dirt – an amazing setting – so it was logical to use a natural available material and colour,” says Randall.

“It’s a remote airport, so bringing in materials wasn’t very sustainable and getting it up there was time consuming and expensive, so once again it was the right choice to use earth from the site.” 

And then there’s the aesthetics. “They’re beautiful,” Randall says simply. 

The rammed earth walls in Port Hedland also carry a deeper meaning – linking the terminal to nearby Karijini National Park, famous for its beautiful cliff faces featuring multi-coloured horizontal striations (banding). 

“When we were doing the concept the idea of the rammed earth walls, having those striations was important for us to reflect the Karijini and the outback.” 

QIC hero render

Planned hotel at Castle Towers by QIC Real Estate showcasing rammed earth.

On Australia’s east coast, a notable potential implementation of rammed earth on a different scale can be seen in Woods Bagot’s design for a proposed 200+-room lifestyle hotel at Castle Towers in north-west Sydney, now going through Development Approval.  

Fraser, who is leading the Castle Towers project design, says conventional thinking is that rammed earth walls, known for their bulkiness and weight, are unsuitable for high-rise constructions.  

However, the Woods Bagot team is exploring an ingenious workaround – a stabilised pre-cast rammed earth panel for the balcony balustrades, significantly reducing its weight while maintaining the appearance of a predominantly rammed earth structure. 

This new solution enables rammed earth to be embraced in tall buildings, expanding its architectural possibilities. 

The proposed hotel is part of a mixed-use development known at The Village, by QIC Real Estate at Castle Towers, encompassing commercial, retail, entertainment, and hospitality precincts.

Drawing inspiration from the unique geological context of Castle Hill, the W-B design team is crafting a visual narrative echoing the surrounding shale rock and sandstone, resulting in a distinct soil mix with reddish and yellow tones.

Fraser says the erosion processes inherent in the local geology influenced the building’s massing, evoking the image of larger blocks breaking off and sliding past each other. The triangular shape of the balconies further enhances the effect.

By employing locally sourced soils, the overall facade will embody the region’s rich earthy hues, showcasing a unique colour palette exclusive to Castle Hill.

“It’s an incredible material,” says Fraser.

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Martin Kelly
Content and Communications Leader (Australia & New Zealand)

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